This invention relates to computers and more specifically to a switch for selectively linking individual computers to a work centre in a secure fashion.
In order to implement high security applications, secure computers are used. One standard for secure computers is the TEMPEST standard. These secure computers prevent access to information stored therein by unauthorised individuals. Commonly, these computers are either stand alone computers or are networked with other similar secure computers. Thus, many high security establishments have what is termed secure networks.
Unfortunately, some individuals within these organisations require access to a wide area network such as the Internet. Any connection to the Internet from a secure network reduces security and is thus not really possible within current secure network standards. Therefore, most high security establishments run two networks simultaneously, one being a secure network and the other being a regular, unsecured, network. Many individuals within these organisations have at their desk two work centres each having a monitor keyboard and mouse and each for controlling a different computer. The computers are spaced by at least a predetermined distance to prevent information in the form of electromagnetic radiation from coupling from the secure system to the unsecured system.
The space occupied by the two work centres is significant in relation to current xe2x80x9ccubiclexe2x80x9d size. This often results in discomfort to employees and in reduced overall productivity. U.S. Pat. No. 5,499,377 discloses a connector for connecting a single monitor and keyboard to a plurality of computers. Such a system reduces the space required for two computers by limiting a system to one monitor, keyboard, and mouse. The system is complicated and does not maintain any security; enhancement of the system to account for security is not straightforward and may not be possible. According to the background in that patent, mechanical switches have been employed for accomplishing selective communication between a work centre and any of a plurality of computers. More effective communication also has been accomplished using electronic switches along with various features such as automatic booting and video signal refinement.
One prior form of switching system utilizes a work centre or console work centre with individual cables extending to each of the several computers. By actuating the console, selective communication can be established through one of the cables for a selected computer. Although such systems have been effective, the volume of cable often is troublesome and difficult to accommodate. For example, numerous cables extending from multiple individual computers to the console frequently present a substantial problem. Accordingly, a need exists for a switching system enabling access from a single work centre (video monitor, keyboard and mouse) to any of a plurality of computers.
Unfortunately, such a system is useless for switching between a secure computer and an insecure computer. Signals within the switching device propagate from one computer to the other. In essence, the resulting system reduces the security of the secure network to that of the unsecured network. This is completely unacceptable in most security related applications. Further, the isolation requirements between systems currently achieved through spacingxe2x80x94are not met with such a switch.
It is an object of the present invention to provide a switch for connecting a single monitor, keyboard, and mouse to a plurality of computers some of which are in communication with secure networks and some of which are in communication with unsecured networks.
In accordance with the present invention there is provided a multi-computer input/output port switching system for accessing a plurality of computers from a single work centre, said work centre including input/output devices, the switching system comprising:
a first coupling system for coupling to a first computer system;
a second coupling system for coupling to second computer system;
a switch having a first port for coupling to the first coupling system, a second port for coupling to the second coupling system, and a third port for coupling to the input/output devices, the switch for selecting one of signals received at the first port and signals received at the second port for provision to the third port; and,
an isolator for electrically and electromagnetically isolating the first coupling system from the second coupling system.
In accordance with the present invention there is provided a multi-computer input/output port switching system for accessing a plurality of computers from a single work centre, said work centre including input/output devices:
a housing having a first compartment, a second compartment, and a third compartment, each compartment shielded to provide electromagnetic isolation therebetween;
a first coupling system for coupling to a first computer system, the first coupling system disposed within the first compartment and comprising a keyboard emulator, a mouse emulator, a plurality of isolating switches, and a first output port;
a second coupling system for coupling a to second computer system, the second coupling system disposed within the second compartment and comprising a keyboard emulator, a mouse emulator, a second plurality of isolating switches, and a second output port;
a switch disposed within the third compartment and having a first port for coupling to the first output port, a second port for coupling to the second output port, and a third port for coupling to the input/output devices, the switch manually operable for providing a control signal to each of the first coupling system and the second coupling system for selectively operating the first plurality of isolating switches and the second plurality of isolating switches wherein switching the first plurality of isolating switches to an closed state is only possible when the second plurality of isolating switches are in an open state.